[CH3:1][O:2][C:3](=[O:17])[C:4]1[CH:9]=[C:8]([N:10]2[CH2:14][CH2:13][CH2:12][C:11]2=[O:15])[CH:7]=[C:6]([OH:16])[CH:5]=1.C([O-])([O-])=O.[K+].[K+].[CH2:24](I)[CH3:25]>CN(C=O)C.Cl>[CH3:1][O:2][C:3](=[O:17])[C:4]1[CH:9]=[C:8]([N:10]2[CH2:14][CH2:13][CH2:12][C:11]2=[O:15])[CH:7]=[C:6]([O:16][CH2:24][CH3:25])[CH:5]=1To 3-hydroxy-5-(2-oxo-pyrrolidin-1-yl)-benzoic acid methyl ester (D37) (0.80 g, 3.4 mmol, 1 equiv) dissolved in DMF (10 ml) was added K2CO3 (0.94 g, 6.8 mmol, 2 equiv) and ethyl iodide (1.1 g, 6.8 mmol, 2 equiv). The resulting mixture was heated at 50° C. for 4 h, cooled to room temperature, diluted with 2N aqueous HCl solution (50 ml) and extracted with Et2O (50 ml). The organic phase was then washed with water (50 ml), dried over MgSO4 and concentrated in vacuo to give of 3-ethoxy-5-(2-oxo-pyrrolidin-1-yl)-benzoic acid methyl ester (B11) (0.85 g, 95%) as a brown oil which slowly solidified to a tan solid.
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